Method of making vane tracks



April 12, 1949. w. FERRlS METHOD OF MAKING VANE TRACKS 1 v 3 Sheets$heet 1 Original Filed April- 10, 1944 I INVENTOR WALTER F ERRIS BY I ATTORNEY April 12, 1949. w FERRIS 2,467,121

METHOD OF MAKING VANE TRACKS Original Filed April l0, 1944 3 Sheets-Sheet 2 INVENTQR WALTER FERRIS ATTORNEY April 12, 1949. w. FERRIS METHOD OF MAKING VANE TRACKS Original Filed Ap il 10, 1944 5 Sheets-Sheet 3 Patented Apr. 12, 1949 METHGD OF MAKING VANE TRACKS Walter Ferris, Milwaukee, Wis., assignor to The Oilgear Company, Milwaukee, Wis., a corporation of Wisconsin (lriginal application April 10, 1944, Serial No.

Divided and this application August 2, 1946, Serial No. 687,989

13 Claims. 1

This application is a division of application Serial No. 530,425, filed April 10, 1944.

The invention relates to a method of making vane tracks for vane type hydrodynamic machines.

The vane track of a hydrodynamic machine includes a plurality of abutments or bridges, with which the vanes coact to provide substantially liquid tight seals between the inlet and the outlet ports of the machine, and a plurality of track sections which are arranged between the bridges and form therewith a continuous track upon which the outer ends of the vanes ride during rotation of the rotor. The bridges are ordinarily arranged in pairs with one bridge of each pair arranged close to the periphery of the rotor and with the other bridge spaced from the periphery of the rotor when the machine is performing useful work, the bridge which is close to the rotor being called sealing bridge and the bridge which is spaced from the rotor being called the pumping bridge or the working bridge. If all the bridges are stationary, the displacement of the machine is constant but the displacement may be varied by providing means to move the working bridge of each pair toward and from the rotor.

Vane type hydrodynamic machines are extensively used as pumps but a properly designed vane type hydrodynamic machine may function as a motor. When the machine is used as a pump, its rotor is ordinarily rotated at such a high speed that the centrifugal force is sufiicient to keep the vanes in contact with the track and it is only necessary to hydrostatically balance the vanes.

However, if the machine is operated at slow speeds, as by being used as a motor, the centrifugal force is insuflicient to keep the vanes in con tact with the track in which case the machine is provided with suitable means for positively moving the vanes outward such as means for supplying high pressure liquid to the inner ends of the outward moving vanes.

When the working bridges of a machine having two pairs of bridges are spaced from the rotor and the rotor is rotated, each vane will move inward as its outer end moves from a working bridge toward the adjacent sealing bridge, it will move outward as its outer end moves from the sealing bridge toward the next working bridge, it will more inward as its outer end moves from that bridge toward the next sealing bridge, and it will move outward as its outer end moves from that sealing bridge toward the first mentioned bridge. Each vane thus makes two reciprocations during each revolution of the rotor and, since the rotor is often driven at very high speeds, the reciprocations may be very rapid.

If the track is so shaped that it forces each vane inward too rapidly, the vane will tend to dig into the track and thus cause excessive wear of the track or the vane or both. If the slope of the track at any point is so steep that an outward moving vane cannot follow it, the vane may leave the track at that point and reengage the track at another point with an impact that tends to damage both the track and the vane. Consequently, the shape of the track must be such as to .provide gradual accelerations and decelerations of the vanes.

A track having a surface so shaped as to cause uniform accelerations and decelerations of the vane would provide an ideal condition which may be approached in a unitary rigid vane track for a constant displacement machine but in a variable displacement machine the contour of the track will vary as the movable bridges are moved inward and outward to vary the displacement.

The present invention has as an object to provide a method of making a vane track having extensible vane track sections which cooperate with bridges to form an endless track of variable length for guiding the vanes of a variable displacement hydrodynamic machine in their inward and outward movements, which track may be supported solely by the bridges and which cooperates with the bridges to form a vane track of a contour that will cause gradual accelerations and decelerations of the vanes in their radial movements.

Another object is to provide a method whereby such extensible vane track sections may be accurately and economically manufactured.

Other objects and advantages will appear from an explanation of the method and a description of a vane track section made according thereto as hereinafter set forth.

A vane track made according to the invention is illustrated in the accompanying drawings in.

which the views are as follows:

Fig. 1 is a transverse section through one half of a pump in which vane tracks constructed according to the invention are incorporated and which shows the pump adjusted to maximum displacement.

Fig. 2 is a transverse section through the opposite half of the pump and shows the pump adjusted to minimum displacement.

Fig. 3 is a view of the inner peripheral face of one of the track sections shown in Fig. 1 and it includes portions of the bridges to which that section is connected.

Fig. 4 is an end or edge view showing the two parts of track section shown in Fig. 3 separated from each other.

Fig. 5 is'a view of the outer sides of the track section parts shown in 4.

Fig. 6 is a transverse section taken on the line 6-6 of Fig. 5.

Fig. 7 is an edge or end from which the principal parts of the track sections shown in Fig. 1 are made.

Fig. 8 is an end or edge view of one section of the element shown in Fig. '7.

Fig. 9 is an outside view of the section shown in Fig. 8 and together with that figure illustrates how the section is divided into parts.

Fig. 10 is an edge view of an element from which the guide segment shown in Figs. 4-6 is made.

Fig. 11 is a diagram illustrating a method for determining. the lengths of the radii of the track surfaces on the bridges and on the track sections of a hydrodynamic machine such as the pump shown in Figs. 1 and 2.

For the purpose or" illustration, a vane track made according to the invention has been shown incorporated in a variable displacement nonreversible pump but it may as readily be incorporated in a reversible pump or in a motor.

The pump shown in Figs. 1 and 2 has a plurality of vanes l slidable in suitable slots formed radially in a cylindrical rotor 2 which is fixed upon ashaft 3 to be rotated thereby. The outer ends of'vanes l engage an endless track upon which the vanes ride when the rotor is rotated. The vane track includes two diametrically opposed sealing bridges 4 and 5, which are fixed in stationary positions close to the periphery of rotor 2; two pumping bridges 6 and l which are spaced 90from'the other two tobe moved toward and from the periphery of rotor 2 to vary pump displacement, and four extensible track sections 8 each of which is arranged between and connected to adjacent bridges; Bridge 1 has been shown arranged close to'rot0r2 to illustrate the position of the parts when pump displacement is zero and bridge 6 isshown spaced from rotor 2 to illustrate the position of the parts isnear maximum.

The rotor and the vane track are arranged between'two cheek plates and within an annular spacer ring all of which is enclosed in a suitable casing. For 1 and 2 has its rotor and vane track arranged inside of an annular spacer ring 9 and between two cheek plates (not shown) which engage opposite sides of ring 9, and the entire assembly is enclosed within a casing Ill.

The bridges are closely fitted between the cheek plates and in suitablerecesses formed in the spacer ring, sealing bridges and 5 being fixed in stationary positions while pumping bridges 6 and 1 are'slidable in the recesses and adapted to be moved inward and outward by any suitable means to vary the displacement of the pump.

The space between the periphery of rotor 2 and the inner periphery of spacer ring 9 communicates with two interconnected diametrically opposed intake ports H and two interconnected diametrically opposed discharge ports l2 which are arranged adjacent to the periphery of the rotor. Each portis arranged between adjacent bridges, and liquid seals between adjacent ports view of an element bridges and are adapted when pump displacement example, the pump shown in Figs.

, H and, as each vane crosses are provided by the bridges and the vanes in contact therewith.

Since vane type pumps are well known and since a typical pump of this type is illustrated and described in U. S. Patent No. 2,141,171 to which reference may be had for details of construction and mode of operation, further illustration or description of the pump is thought unnecessary, it being deemed sufificient to state that, when rotor 2 is rotated in the direction of the arrow and the pumping bridges are spaced from the rotor, the vanes will move progressively outward as the outer ends thereof move along the vane track from a sealing bridge to a pumping bridge and they will be forced inward by the track as the outer ends thereof move along the track from a pumping bridge to a sealing bridge. The spaces between the outer ends of the outward moving vanes will be filled with liquid from intake ports a pumping bridge, the liquid between it and the preceding vane will be discharged through a port [2."

If the track surface on each track section were of such a length that one of its ends would-abut the ends of the track surface on the adjacent sealing bridge when pump displacement was zero and its other end would abut the track surface on the adjacent pumping bridge when pump displacement was maximumone end or the other of the section wouldmove away from the track surface on the adjacent bridge as the pumping bridge moved in one direction or theother so that therewould at all times be a gap in the vane track at one or both ends of each track section.

In order that the track sections may be connected to the bridges provide an unbroken path for the vanes. each stationary bridge has a portion 5 at opposite sides thereof reduced in thickness, each movable bridge has a portion I'I at opposite sides thereof reduced in thickness, each track section 5 has notches orrecesses l8 and it formed in opposite ends thereof to receive reduced portions l6 and l'!, and the matched end portions of each track section are provided with holes 20 and by means of win ch each track section is pivotally connected to adjacent bridges, the notched porticns of the track section overlapping the reduced portion of the bridges to provide an unbroken track'suriace as shown in Fig. 3.

Each track. section 6 includes two principal a circular T-shaped parts 26 and 21, which have groove 28 formed therein and extending through the outer periphery thereof, and a circular T :iaped guide segment Z'QWhich is fitted in groove 23. The inner peripheral faces of parts 26 and are finished to the same radius to provide a smooth track surface for groove 28 is formed concentric surface so that 26 and permitting guide segment 29 may holdparts the two partsto move relatively. to each other in a circumferential direction to vary the length of the vane track. The arrangement is such that each track section 8 is pivotally supported at both of its ends and it is self supporting intermediate its ends. Segment 29 is preferably fixed to one of the two parts, such as part as by means of a pin 39.

The adjacent ends of shaped as to provide an unbroken path-for the vanes they pass from one part to the other. For example, the inner end of track surface on the track 2| to receive pins 22' and 23- guidin the vanes and" with this track in alinement with each other while parts 26 and 27 aresoj part 25 may havetwo oppositely inclined'face's' 3| whichconver'ge" upon the centerline of the track and the inner end of part 2'! may be provided with oppositely inclined faces 32 which diverge from the centerline of the track so that the end of part 21 is complementary to the adjacent end of part 26 as shown in Fig. 3. This arrangement provides a bearing for nearly the entire width of each vane while it passes from one to the other of the two parts of each section.

The vanes move radially when the pump is discharging liquid and the radial accelerations of the vanes must be maintained within certain limits in order that the outward moving vanes may remain in contact with the track and in order that the vanes being forced inward by the track may not bear so heavily against the track as to cause excessive friction and wear.

If the track surfaces of track sections 8 and bridges l, 5, 6 and 1 were concentric with the rotor, the track would be substantially circular when the displacement of the pump was zero at which time the vanes would have substantially no radial movement but when the pump was adjusted to maximum displacement, at which time the radial movement of the vanes would be maximum, the track surface on each track section 8 would form an angle with the track surface on the adjacent bridge. The accelerations of the vanes riding upon the concave track surfaces may be maintained within the permissible limits but, as each vane passed across the angle at the junction of a track section surface and a pumping bridge surface, its radial movement would be suddenly reversed and hence uncontrolled at the very instant that it was performing a maximum amount of work. Also, since the bifurcated end of a track section overlaps the reduced portion on the adjacent bridge in order to provide an unbroken path for the vanes, the end of a track section would extend above the track surface of the sealing bridge to which it was connected and the end of that bridge would extend above the track surface of the same track section and thereby form obstructions in the path of the vanes when pump displacement was at or near maximum.

In order to prevent damage to either the track or the vane and to keep the accelerations of the vanes from being excessive, the bridges are provided with concave track surfaces having a suitable radius. the track sections are provided with concave track surfaces having preferably such a radius that the track surfaces of a track section and the adjacent pumping bridge will be tangent at their junction when pump displacement is maximum andthe track surfaces of a track section and the adjacent sealing bridge will be nearly tangent at their junction when pump displacement is zero, pivot pins 22 and 23 are arranged as far radially outward as may be convenient within the available space, the concave surfaces on each track section and the adjacent sealing bridge are joined by a convex surface when pump displacement is maximum and the concave surfaces on each track section and the adjacent pumping bridge are joined by a convex surface when pump displacement is minimum so that the concave track surfaces on a track section and one adjacent bridge are joined by a smooth transition curve when the track surfaces on that section and the other adjacent bridge are tangent or nearly tangent. The radii of the track surfaces may be determined in a manner to be presently explained, The transition curve causes the vanes to move radially as they pass over it but the curve is such that the accelerations and decelerations of the vanes at this point are well within the permissible limits. With this arrangement, the radial movement of a vane is very little when it is performing a maximum amount of work, that is, when pump displacement is maximum and the vane is passing across the pumping bridge.

The convex track surfaces may be formed upon the vane track sections but, for the purpose of illustration. they have been shown on the bridges and the ends of the track sections have been shown chamfered as indicated at 33 and 34 in Fig. 4 so that they will not extend above the track surfaces of the bridges.

The vane track may be accurately and economically made by the following method:

An annular element 35 of the approximate size of the complete vane track is so formed, as by casting, to include a plurality of unfinished track sections 8 from which finished track section parts 2.8 and 21 may be made. Element 35 could include more than four unfinished track sections 8 but, for the purpose of illustration, it has been shown in Fig. '7 as including four unfinished track sections 8 and four separators d 5 6 and I all of which are formed integral with each other and correspond, respectively, to the track sections 8 and the bridges l, 5, E and 1 shown in Figs. 1 and 2.

The inner periphery of element 35 is ground or otherwise finished to provide a smooth track surface having a radius 36 which is ordinarily less than the radius of the rotor of the pump in which the track sections are to be used and is preferably determined by a method to be presently explained.

An annular groove is formed in the outer periphery of element 55 and it is made wide enough to accommodate the radial length of guide element 29 as shown in Fig. 6. The groove is extended inward until its inner wall has a radius 31 which is enough greater than radius 36 to provide a web of sufiicient thickness between the groove and the track surfaces. The groove is then extended laterally between radius 31 and a greater radius 38 to provide spaces for the axial length of segment 29, thereby forming an annular T- shaped groove 28 which corresponds to the groove 28 shown in Figs. 4-6. While holes 20 and H may be formed at any time. they are preferably formed by drilling through a template which may be readily adjusted upon element 35.

Element 35 is then cut at each end of each section 8 to sever the four sections from the separators. Notches l8 and ii! are then formed in the ends of each section either by machining from the solid or by finishing to size openings. which were provided in element 35 when it was formed. The ends of each section 8 are chamfered, as indicated at 33 and 34, and the section is cut into two parts 26 and 21 by two saw cuts 39 and 40 which preferably are normal to the chord of the section, as shown in Fig. 8, and extend inward from opposite sides of the which is preferably about 45 as shown in Fig. 9.

The guide segments 29 are made from an annular element 4! (Fig. 10) which is T-shaped in cross-section and consists of a plurality of segments 29 each of which corresponds to a guide segment 29. Element M is inside to a radius 3T upon the outside of its flange to a radius 3:8 and upon its sides to a width slightly less than the width of groove 28. Radii 51 and 38 vary in length from radii 31 and 38 just enough to enable the segments cut from element M to section at an angle machined upon its have a sliding fit in groove 28,

ag ievgiai Elemental: is then divided into segments 29 by' sawv cuts 42 an'd"the= ends "of-the segments are beveled? as indicated cit/t3; either before or after rahty of'bridges'may befastened to a-fixtureand of all of 'those bridges first machined', as by boring, and thenfinished-as by grinding to provide asmooth-tracicsurface on eachbridge but it is not His-on 2'1 and istangent tothe concave surface, the convex surfaces preferabiybeing formed after th'eicon'oave' surface is finished.

Aimethod for determining the radii of the track surface' on the bridgesand on the track sections ofia hydrodynamic machine, such the num showntin Figs. 1 and 2, is illustrated in Fig. 11 iniwhich asealing bridgeand one pumping bridge, such." as bridgesfi and 'i, are shown inthe positions occupiedlwhenpu 1p displacement is zero and the otheizpumping bi idge, such as t is shown in the'rposition. occupied when pumpdisplacement ismaximumc As. shown in Fig. 11, the concave surface eachtbridge': has -aradins 55- which is slight greaterirthaof the rotor but the radius mayrbeand. in practice sometimes is siightiy less than: the-.radius'ofithe rotor. With the'radius as shownrand. with pump displacement at zero,- ali ofi the concave surfaces on ail of thebridges are concentric 'withbut spaced slightly from the periph'ery' of the rotor and" their radius extends from a-center Ci which is also the axis of the rotor." Wherra pumping bridge such as bridge lnTitS maximum: displacement position, the radius of its concave surface extends from a center C2" and tangent. to the concave-surface at the'radiuswhich passeslthrough that pin. For example, eachsealing-bridge',suchas bridge 5, has at each end thereof a. convex track surface the adjacent pin 22, and=each pumping bridge,

such: as. bridge 5, has at eachend thereof a convextr-ack surfacefifi which is tangent to concave surface 53 at radius M or 5i and has a radius 57 which is struckfrom the center of the adjacent pin 23 In ordei that a: track section may have one end of itstrack. surface tangentto the concave surface: on the adjacent. pumping bridge when segment andinth'e track sec-- thedistance through which the extends indicated by center Cit.

pump'--di'splacement is maximum the track sur face on*the tracksection hasthe center of its arc locatedat a point on the radius whichextends from center in" the pumping bridge and; in order that the other end; of thetrack section surface may be t-an-gent' to the track surfaceon the sealing bridge, the center point ls-located on that radius equidistant from the concave surface on the-pumping bridge-and a: point on the adjacent convex-surface on th sealing bridge.

A'sshown thetrack surface of track section thasa radius tifi'struck from acenter C3 which is locatedonradius 5-l' equidistant from "concave surface ai and-the-point nearest to center G3 on the'adjacentconVex surface ii i-sothat the track face iit' at a radius 35 which extends from center Ctthrough the adjacent pivot pin 22;

will' continue to move radially. in the same direction while passing across a convex surface but at that time the vanes-are performinglittle orcno: work and the radial accelerations and decelerations of the vanes may be readily determined and are Well withinthe permissible limits. These accelerationsand deceierationsniay-be further reduced by moving pins and 23 farther outward.

When-the pumping-bridges are moved inward to reducepump displacement,- will-move inward ll move closetocenter Ci as 'whichvis the center of the are on the track section 8 which is'arranged between bridges 5 and 1.

Asthe pumping bridges move inw-ard one end of: the concave trackrsurface on each track section-3'movestoward concave track surface 52 toreduce the: convex transition curve between the two concave curves, and the otherendfiof the concave track section surface moves very slowly out oftangency with the ad- .jacent'surface 53; and into tangency with the con-vex suri ace Etwhich then provides a small convexitrans'ition curve between the concave curves buts-the transition curve on surface 55 is so shortieven at zero displacement as to be substantially negligible; That is, the length of the convex transition curve between concave surface and-"the adjacent concave track section surface is the distance between radius-5i and the radius 35 surface is thedistanc'ebetween the radius 5 l and through-the adjacent-pivot pin 22 O2 through the adjacent pin one track section 8' 9 displacementthe distances between radius and radius 36* and between radius 5! and radius 36c are substantially negligible, the vane track is substantially circular when pump displacement is zero except for the fact that track radius 35 has been made smaller than bridge radius iii to produce the tangent conditions of adjacent concave and convex arcs just described. lhis shortened track radius 3% causes a very slight radial movement of each vane which has no significance because the vane is unloaded at this time.

The invention thus provides a method of accurately and economically making vane tracks which cause the vanes in contact therewith to gradually accelerat and decelerate as they move radially in the rotor.

The method described herein may be varied to some extent without departing from the scope of the invention which is hereby claimed as follows:

1. The method of making adjustable vane track sections for a hydrodynamic machine having a rotor and an endless vane track arranged around said rotor and including alternate track sections and bridges and being adjustable to vary its length and thereby vary the displacement of said machine, said method comprising the steps of forming an annular member which is of the general shape and size of said track and has a plurality of sections corresponding to the adjustable sections of said vane track, finishing the inner periphery of said member to provide a smooth circular track surface, forming in said member at least one annular groove which is spaced from said track surface and has radially opposed bearing faces, cutting said member into pieces to separate said sections, providing a connection at each end of each section for pivotally connecting the sections to said bridges, cutting each section diagonally to divide it into two parts and to provide an unbroken path for the vanes passing from one part to the other, making a plurality of guide segments which are complementary to the grooves in said parts, and inserting a segment in each of said grooves to hold the two parts of each track section in alinement while permitting the section to be extended or contracted.

2. The method of making adjustable vane track sections for a vane type hydrodynamic machine having four bridges spaced about 90 apart and track sections arranged between said bridges and forming therewith an endless vane track, at least two diametrically opposed bridges being adjustable to vary the length of said track, said method comprising the steps of forming an annular member of the general shape of said vane track, finishing the inner periphery of said member to provide a smooth circular track surface, forming in said member at least one annular groove which is spaced from said track surface and has radially opposed bearing faces, cutting said member into eight pieces four of which are semi-finished track sections, providing a connection at each end of each section for pivotally connecting the sections to said bridges, separating each section into two parts by making two oppositely inclined cuts which extend from opposite sides of the section inward far enough to separate the two parts, making a plurality of guide segments which are complementary to the grooves in said parts, inserting a segment in each of said grooves to hold the two parts of each track section in alinement while permitting the section to be extended or 10 contracted, and fastening said segment to one of said parts.

3. The method of making adjustable vane track sections for a hydrodynamic machine having a rotor and an endless vane track arranged around said rotor and including alternate track sections and bridges and being adjustable to vary its length and thereby vary the displacement of said machine, said method comprising the steps of forming an annular member which is of the general shape and size of said track and has a plurality of sections corresponding to the adjustable sections of said vane track, finishing the inner periphery of said member to provide a smooth circular track surface, forming in said member at least one annular groove which is spaced from said track surface and has radially opposed bearing faces, cutting said member into pieces to separate said sections, providing a connection at each end of each section for pivotally connecting the sections to said bridges, cutting each section diagonally to divide it into two parts and to provide an unbroken path for the vanes passing from one part to the other, forming a ring which is complementary to the groove in said member, cutting said ring into segments, and inserting a segment into each of said grooves to hold the two parts of each section in alinement while permitting the section to be extended or contracted.

4. The method of making adjustable vane track sections for a hydrodynamic machine having a rotor and an endless vane track arranged around said rotor and including alternate track sections and bridges and being adjustable to vary its length and thereby vary the displacement of said machine, said method comprising the steps of forming an annular member which is of the general shape and size of said track and has a plurality of sections corresponding to the adjustable sections of said vane track, finishing the inner periphery of said member to a radius less than the radius of said rotor to provide a smooth circular track surface, forming in said member at least one annular groove which is concentric with said track surface and has radially opposed bearing faces, cutting said member into pieces to separate said sections, providing a connection at each end of each section for pivotally connecting the sections to said bridges, cutting each section diagonally to divide it into two parts and to provide an unbroken path for the vanes passing from one part to the other, making a plurality of guide segments which are complementary to the grooves in said parts, and inserting a segment in each of said grooves to hold the two parts of each track section in alinement while permitting the section to be extended or contracted.

5. The method of making adjustable vane track sections for a hydrodynamic machine having a rotor and an endless vane track arranged around said rotor and including alternate track sections and bridges and being adjustable to vary its length and thereby vary the displacement of said machine, said method comprising the steps of forming an annular member which is of the general shape and size of said track and has a plurality of sections corresponding to the adjustable sections of said vane track, finishing the inner periphery of said member to provide a smooth circular track surface, cutting into said member from the outside thereof an annular groove which is T shaped in cross-section, cutting said member into pieces to separate said sections, providing a connection at each end of each section age-7,121

'zfor ,pivotally. connecting thee-sections to :said

bridges, cutting each section diagonallytoadivide it into ,two. parts and, to provide an unbroken path for-the :vanes passing, frompne part toithe other, :maki-ng, aig-uide segment whichiscomplementary ,tothe Ts'shapedgroove inatrack section,n and inserting. said segment into the 'T-shaped grooves inthe-two halves of. a-track section.

, 6. ,The method of making adjustable vaneitrack .sectionsfora vane type hydrodynamic machine having four bridges spaced about .90 apart and track .sectionsarranged between said bridges .and ,forming therewith tan endless vane track, at leastrtwodiametrically opposed bridges being adjustable ..to vary method -.com prising the steps 7 of forming anv annular-,member of the general shape of sai'dvane ,track,-finishing the inner periphery ofsaidmemher ,to ,provide a smooth circular :track surface, cuttingdntosaid: member from the outsideth'ereof :an.-annular=groove which-is T-shapedincrosa section, -cutting said "member into eight pieces four-:ofewhich zare semi-finished track sections, providing a connection at each end of' each section for ,pivotally connecting 1 the sections "to said bridges,separating eachsectioninto tworparts by means of cuts which extend diagonally'inward fromiqppositef-sides of the section and-meet each OthQIYiOIYIl-ihg a :ring which is complementary to the T-shaped groove in said member, :cutting said-ringtinto segments,and inserting oneqo'f said segments into the l -shaped groove-in a;.track section ;to prevent .radial displacement ;of ,one halt-:sectionmelative:-to:the other half-section.

:7. ..The methodof makingacljustable vane :track sections ;for a hydrodynamic machine-having a rotoriand Kan endles vane track arrangedaround said rotor and-includingalternate track sections and bridges and "being adjustable to avary its length :andthereby vary. the displacement of 1 said machine/said method-.comprising the 'steps of casting; from. iron an -;annular member'whichis of the eneralshape ,a-ndisize of said track andhas asplurality of sections corresponding :to the:;ad justableasections of said vaneitrack, .machining saidnmember upon-both sides; thereof tofinish: it to apredetermined width, adjustinglsai-djmemher .on. a. machine, boring said member to -a- -predetermined radiustoiform. a track surface upon theminner periphery thereof, .forming .in said member Without altering the adjustment; thereof atlleast one annular groove .whichis spaced from s'aid'track surface and has radially opposed bearing"'faces, grinding said track surfaces, boring through 'a template attached to said member holesi'in the ends of said sections forpivot, pins to connect said. sectionsto saidbridges, cutting said'mem'ber into pieces to separate sa'id sections, cutting eachsection diagonally to divide it into two parts and to provi'de an unbroken .path for the vanes passingfrom one part tothe other, making a plurality of guidesegmentswhich are complementary tothe groovesin said parts, and inserting a segment in each of-saidmgrooves. to holdthetwo parts of each'track section in alinement 'While permitting the section to be .eX- tended'or contracted.

8; The. method of ,makingan adjustable vane track :to extend around the .rotor :ofiashydrodw namic machine and to include alternatebridges and track sections, comprisin the. steps of ,forming a concavetrack surface upontheinneriace of v.aplurality of. bridges, forming .a-convex surfaceat each .end of .the concave surface on ,each of Lth'e bridges, ,forming a pin holein ,eachsside thedengthof said track, said of-each bridge, forming a plurality'of unfinished necting the sections to said bridges, cutting each section diagonallyto divide it into two parts and to provide an unbroken path for the vanes passing from one part to the other, making a plurality of guide segments which are complementary to .the grooves in said parts, insertinga segment into the grooves in said parts to hold the two parts of each section in alinement while permitting the section to be varied in length, arranging a pluralityofsaid-sections and an equal number of bridges alternately around a common center, and-.pivotally connecting opposite ends of each of those track sections to the adjacent loridgesby inserting .pinslinthe pinholes formed therein.

9.,The method of making an adjustable vane track to extend around the rotor of ahydrodynamic machine .andto include alternate bridges and track sections, comprising the stepsoi a1- rangin apluraiityof unfinished bridges in fixed positions equidistant from a common center, formin concave track surfaces .uponthe inner i'acesof all of said bridges simultaneously, forming apin holein each side of each bridge, forming at each endof the concave surface on each of the bridges a convexsuriace which is tangent to the .concave suri'aceand is concentric with the adjacentpin hole, forming a plurality of unfinished. track sections, I'inishingthe inner face of each tracksection to provide asmooth concave track surface, forming in each section at least one groove which isconcentric with and spaced from the track surface thereon and which has radially opposed bearin faces, forming a pin hole'in-each end of .each section for pivotally connecting the sections to saidbridges, cutting each section diagonally to divideit into two parts and to provide .annnbrroken ,path ,icr .the vanes pass-- ing from one part to the other, making a plurality of guide segments which are cornple mentary to the grooves in said parts, inserting a segment. into the groovesin. said parts to hold the twoparts of eachsection inaiinernent while permittin the section to be varied .in length, arrangin a plurality of said sections and-an equal number of bridges alternately around a common center,. and pivotally connecting opposite ends of each of those track sections to the adjacent bridges by inserting pins in thepin holes formed therein.

. 1 0.. The method of making an adjustable vane track to extend around the rotor of a hydrodynaniicmachine and toinclude alternate bridges and track sections, oomprisingthe steps oi forming a concave track surface upon the inner face ofa plurality of bridges, forming a convex surface at each end of the concave surface on each of the bridges, providing at each side of each bridgeiaconnectionfor a track section, forming an,annular member having a plurality of integral sections which correspond to said. tracksections, finishing the inner periphery of said mom" to provide asmooth circular track surface, forming in said member at least one annular groove which is spaced from said surface and has radially opposed bearingfaces, cutting said member into piec-esto separate sa'idsections,

providing a connection at each end of each section for pivotally connecting the sections to said bridges, cuttin each section diagonally to divide it into two parts and to provide an unbroken path for the vanes passing from one part to the other, making a plurality of guide segments which are complementary to the grooves in said parts, inserting a segment into the grooves in said parts to hold the two parts of each section in alinement while permitting the section to be varied in length, arranging a plurality of said sections and an equal number of bridges alternately around a common center, and pivotally connecting opposite ends of each of those track sections to the adjacent bridges.

11. The method of making an adjustable vane track to extend around the rotor of a hydrodynamic machine and to include alternate bridges and track sections, comprising the steps of forming a concave track surface upon the inner face of a plurality of bridges, forming a pin hole in each side of each bridge, formin at each end of the concave surface on each of the bridges a convex surface which is tangent to the concave surface and is concentric with the adjacent pin hole, forming an annular member having a plurality of integral sections Which correspond to said track sections, finishing the inner periphery of said member to provide a smooth circular track surface, forming in said member at least one annular groove which is spaced from said track surface and has radially opposed bearing faces, cutting said member into pieces to separate said sections, forming a pin hole in each end of each section for pivotally connecting the sections to said bridges, cutting each section diagonally to divide it into two parts and to provide an unbroken path for the vanes passing from one part to the other, makin a plurality of guide segments which are complementary to the grooves in said parts, inserting a segment into the grooves in said parts to hold the two parts of each section in alinement while permitting the section to be varied in length, arranging a plurality of said sections and an equal number of bridges alternately around a common center, and pivotally connecting opposite ends of each of those track sections to the adjacent bridges by inserting pins in the pin holes formed therein.

12. The method of making an adjustable vane track to extend around the rotor of a hydrodynamic machine and to include alternate bridges and track sections, comprising the steps of arranging a plurality of unfinished bridges in fixed positions equi-distant from a common center, forming concave track surfaces upon the inner faces of all of said bridges simultaneously, forming a convex surface at each end of the concave surface on each of the bridges, providing at each side of each bridge a connection for a track section, forming an annular member having a plurality of integral sections which correspond to said track sections, finishing the inner periphery of said member to provide a smooth circular track surface, forming in saidmember at least one annular groove which is spaced from said track surface and has radially opposed bearing faces, cutting said member into pieces to separate said sections, providing a connection at each end of each section for pivotally connect ing the sections to said bridges, cutting each section diagonally to divide it into two parts and to provide an unbroken path for the vanes passing from one part to the other, making a plurality of guide segments which are complementary to the grooves in said parts, inserting a segment into the grooves in said parts to hold the two parts of each section in alinement while permitting the section to be varied in length, arranging a plurality of said sections and an equal number of bridges alternately around a common center and pivotally connecting opposite ends of each of those track sections to the adjacent bridges.

13. The method of making an adjustable vane track to extend around the rotor of a hydrodynamic machine and to include alternate bridges and track sections, comprising the steps of arranging a plurality of unfinished bridges in fixed positions equi-distant from a common center, forming concave track surfaces upon the inner faces of all of said bridges simultaneously, forming a pin hole in each side of each bridge, forming at each end of the concave surface on each of the bridges a convex surface which is tan ent to the concave surface and is concentric with the adjacent pin hole, forming an annular member having a plurality of integral sections which correspond to said track sections, finishing the inner periphery of said member to provide a smooth circular track surface, forming in said member at least one annular groove which is spaced from said track surface and has radially opposed bearing faces, cutting said member into pieces to separate said sections, forming a pin hole in each end of each section for pivotally connecting the sections to said bridges, cutting each section diagonally to divide it into two parts and to provide an unbroken path for the vanes passing from one part to the other, making a plurality of guide segments which are complementary to the grooves in said parts, inserting a segment into the grooves in said parts to hold the two parts of each section in alinement while permitting the section ranging a plurality of said sections and an equal number of bridges alternately around a common center, and pivotally connecting opposite ends of each of those track sections to the adjacent bridges by inserting pins in the pin holes formed therein.

WALTER FERRIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS to be varied in length, ar- 

